We knew him as H.M. from the beginning. He is by far the most important and famous patient in the neuroscience field. You can find his initials in many neuroscience textbooks, and numerous articles.

What gave him this fame?

It was 1935. The Germans were not in Poland yet, and the World War II has not begun. It was an ordinary day in California and H.M. had an unfortunatebicycle accident at the age of nine. His tragedy started from that day; suffering from intractable epilepsy. In 1953, HM was referred to William Scoville, a surgeon at Hartford Hospital, for treatment. This is how the most striking experience a human ever lived in neuroscience started. He got the operation for his epilepsy. On September 1, 1953, Scoville removed parts of HM’s MTL on both sides of his brain. HM lost approximately two-thirds of his hippocampus, parahippocampal gyrus, and amygdala. His hippocampus appeared entirely nonfunctional because the remaining 2 cm of hippocampal tissue appears atrophic and because the entire entorhinal cortex, which forms the major sensory input to the hippocampus, was destroyed. Some of his anterolateral temporal cortex was also destroyed (See the relevant entries Hippocampus: the seahorse that rides you and Amygdala: Yes, I love you and I remember you.)

He lost his short-term memory. His skill to take information and keep it as a long-term memory was gone with the epileptic tissues removed. The case was published in 1957, and his brain has been examined since then. There was nothing wrong with his ability to solve problems, he used to enjoy cross-word puzzles. He died at the age of 82, shedding light on the darkness on memory and teaching to the neuroscience community on the concept of memory through his sequelae after the epileptic surgical intervention.